For clarity, the present invention will primarily be illustrated for use in a monochromatic xerographic marking system; however, this invention can be used equally well in color xerographic systems.
A typical electrophotographic or xerographic reproduction machine employs a photoconductive member that is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the photoconductive member is exposed to a light image of an original document being reproduced. Exposure of the charged photoconductive member selectively dissipates the charge thereon in the irradiated areas to record an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document.
After the electrostatic latent image is recorded on the photoconductive member, the latent image is developed by bringing a developer material into contact therewith. Generally, the electrostatic latent image is developed with dry developer material comprising carrier granules having toner particles adhering triboelectrically thereto. The toner particles are attracted to the latent image, forming a visible powder image on the photoconductive surface. After the electrostatic latent image is developed with the toner particles, the toner powder image is transferred to a sheet. Thereafter, the toner image is heated to permanently fuse it to the sheet.
It is highly desirable to use an electrostatographic reproduction machine of this type to produce color prints. In order to produce a color print, the electrostatographic reproduction machine includes a plurality of stations. Each station has a charging device for charging the photoconductive surface, an exposing device for selectively illuminating the charged portions of the photoconductive surface to record an electrostatic latent image thereon, and a developer unit for developing the electrostatic latent image with toner particles. Each developer unit deposits different color toner particles on the respective electrostatic latent image. The images are developed, at least partially, in superimposed registration with one another, to form a multicolor toner powder image.
The resultant multicolor powder image is subsequently transferred to a sheet. The transferred multi-color image is then permanently fused to the sheet forming the color print.
In both monochromatic and color systems, several stations including charging stations, exposure stations, developer stations, transfer stations, etc. are used. Each station has several delicate components that must be in controlled environments to maintain proper temperatures, humidity and other system conditions. To effectuate this control, an environmental unit (EU) is used. The prior art environmental units (EU) include a rotary positive blower to move conditioned air from the EU into the print engine of the xerographic system in order to maintain and control temperature and humidity. The use of an EU is necessary in most xerographic marking systems in order to produce quality prints. Most blowers introduce pulsations into the air stream at a frequency of about 200-400 Hz which is a function of the motor RPM and the number of blades on the impeller. This pulsation causes vibration throughout the xerographic stations and eventually results in banding problems in the image created. These spaced streaks on the print or image reflect the pulsation or vibration caused by the EU blower. Obviously, these visibly flawed images are not acceptable and require correction.
In order to correct this banding problem, cushions or soft pads were positioned around all shock mountings, which involved a considerable amount of time and cost for each of several mounts and yet did not fully correct the vibration problem that caused the image banding. This prior art corrective measure is illustrated in FIG. 3 of this disclosure. A more effective economical and simpler way to correct this banding problem is needed.